Shopify Dynamic Delivery Cost Integration

I need our Shopify checkout to quote delivery fees that vary by both the physical size of each product and the customer’s distance from our warehouse. The underlying data already exists in a courier-supplied rate card (PDF). Your task is to translate that rate card into a working calculation inside Shopify so that every order receives an accurate real-time charge.

Here’s the situation in more detail.
• Cost model: variable by product size + distance—no flat rates.
• Source data: a PDF showing the courier’s pricing steps for different volumetric tiers and kilometre bands.
• Formula: not yet codified. I’ll provide the PDF; you’ll extract the rules, structure them into a table or JSON, and build the logic.
• Tech stack: whatever is most efficient within Shopify—Shopify Functions, the new Shipping & Delivery profiles, Script Editor, or a custom-built app that pulls the rules at checkout.

Deliverables
1. Digital version of the rate card ready for programmatic use (CSV, JSON, or embedded table).
2. Code or configuration that applies the correct charge at checkout, fully tested across common size/distance scenarios.
3. Brief setup notes so I can update rates when the courier revises the PDF.

Acceptance criteria
– A test order for each size tier at three distance bands must display the exact fee shown on the PDF.
– No impact on existing payment or discount flows.
– Changes deployable to production without requiring Shopify Plus.

If you have previous experience building distance-based or volumetric shipping rules on Shopify, especially through Functions or custom apps, I’d love to see it.